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Context: Forest management practices that conserve biodiversity and maximize carbon sequestration under climate change are needed. Although post-windthrow salvage logging and scarification can reduce carbon dioxide (CO2) emissions within ecosystems by removing downed logs, they can greatly affect species composition. Additionally, salvage logging may increase CO2 emissions based on a cradle-to-grave analysis of salvaged wood. Objectives: We aimed to assess the effects of changes in climate, windthrow regimes and post-windthrow management on aboveground biomass, species composition, and carbon balance in the forest sector by combining forest landscape simulations and life cycle assessment (LCA). Methods: The study landscape is a 12,169 ha hemiboreal forest located in northern Japan. We simulated 115 years (2015–2130) of forest dynamics in 36 scenarios based on features of the climate, windthrow regime, and management using the LANDIS-II forest landscape model. CO2 emissions related to management and salvaged wood were estimated by LCA. Results: Increases in the windthrow area, which was more vulnerable to climate warming, caused a shift to temperate broadleaved forests and a decrease in aboveground biomass. These were accelerated by the removal of advanced seedlings and dead wood, which greatly reduced the recruitment of Picea species. The 115-year cumulative net CO2 absorption of the forest sector, including carbon balance within ecosystems and CO2 emissions estimated by LCA, greatly decreased due to salvage logging (maximum 81%) and scarification (maximum 114%). Conclusions: Leaving downed logs and advanced seedlings is recommended to conserve boreal conifers and carbon sinks and maximize net CO2 absorption under climate change. [ABSTRACT FROM AUTHOR]

The contribution of sapling banks to the coexistence of species with different shade tolerance under the "wave regeneration" regime has not been researched extensively. This study first assessed spatial and temporal variations in the relative dominance of two Abies species, Abies veitchii and Abies mariesii, with different shade tolerance in a wave‐regenerated forest. Second, we present the age structure and its spatial variation in young Abies stands (sapling stage) to exhibit the prevalence and variability of regeneration from sapling banks (defined as trees established 10 years before canopy opening). The relative dominance of A. mariesii, the more shade‐tolerant species, compared to that of A. veitchii, did not change over a period of 10 years, irrespective of stand developmental stages, indicating the importance of initial dominance in determining the local species composition. The tree ages at the sapling stage were significantly higher for A. mariesii than for A. veitchii. Approximately, 30% of all trees were likely to arise from a sapling bank, and 86% of them were A. mariesii. Age structure significantly varied between 5 × 5 m quadrats; some quadrats were dominated by A. mariesii originating from sapling banks, while others were dominated by A. veitchii that were established at the time of canopy opening. These results indicate that regeneration from sapling banks contributes to the dominance of A. mariesii and that the spatial variation in the abundance of trees originating from sapling banks is essential for the coexistence of A. mariesii with A. veitchii. [ABSTRACT FROM AUTHOR]

Although successional changes in the functional diversity (FD) of plant communities have been reported in earlier studies, the processes driving these changes remain unclear. Based on the datasets of a long-term tree census conducted during a secondary succession, we comprehensively investigated the FD and its rate of change during a secondary succession in cool, temperate secondary forests in Chichibu, Central Japan. Data from more than 30-years of observations in plots of secondary forest stands with a wide range of stand ages were used to test changes in species diversity, community-weighted means (CWMs) of each trait, FD, and their change rates. Although species diversity decreased constantly with stand age, the FD (Rao's Q) of all traits decreased significantly at the mid-successional stage, corresponding to the stem-exclusion stage. Changes in CWMs of traits indicated the directional shifts of species composition from resource-acquisitive to resource-conservative along succession, especially at the stem exclusion stage. Although the FD of each trait changed differently with succession, that of several resource-conserving traits decreased significantly at the stem exclusion stage. Based on long-term multiple chronosequence resampling, we found that stem exclusion significantly decreased the FD along a secondary succession in cool temperate forests. This sheds light on the critical role of the stem exclusion stage in shaping plant community traits, indicating the importance of this stage in forest management strategies. • We used long-term tree census data from secondary forest succession. • Analyzing functional diversity change over time using long-term and multiple chronosequence resampling techniques. • Finding the decrease in functional diversity as forests advance through the stem exclusion stage. • Highlights the crucial role of stem exclusion phase in shaping plant trait diversity. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study quantified the numbers and sex ratio of adult Sericania hidana (Coleoptera: Scarabaeidae) in a subalpine forest in 2017. Data from an area littered with coarse woody debris (CWD) created by a typhoon in 1959 were compared with those from an area where CWD had been cleared by salvage logging. Three types of traps were used: flight interception traps (FITs) with a black light, pitfall traps (PITs), and soil emergence traps (SETs). Carbon and nitrogen stable isotopes were analyzed to evaluate S. hidana diets and habitats. Overall, there were more S. hidana in the unsalvaged sites than in the salvaged sites. The FITs captured only males but SETs captured both males and females. The SETs on CWD captured more S. hidana than did SETs on soil in both the salvaged and unsalvaged sites. The PITs captured only a few individuals; thus, PITs are not suitable for studying this insect, although such traps were previously reported to capture S. hidana adults. Stable isotope analyses suggested that S. hidana feeds on a variety of plant materials, including living plants and CWD. These results suggest that CWD has long-term effects on insect populations. Soil emergence traps provide an effective method to quantitatively evaluate insect ecology, and FITs can effectively screen for the existence of insects. [ABSTRACT FROM AUTHOR]

Highlights • Storm disturbance 55 years ago does not affect current wood decay fungal communities. • Disturbance and wood decay type have significant impacts on bryophyte communities. • Disturbance and wood decay type have significant effects on seedling density. • Bryophyte species affect tree seedling density. Abstract Storm disturbance has a huge impact on subalpine forest ecosystems. Evaluating the long-term effects and mechanisms of storm disturbance is of great significance for conservation of subalpine forests as frequency and intensity of storms are increasing because of the climate change. Species of subalpine conifer tree genera such as Picea and Tsuga need coarse woody debris (CWD) such as logs and stumps for seedling colonization; thus, their establishment is greatly affected by the condition of CWD, which largely depends on the activity of fungal decomposer communities and saproxylic bryophyte communities. Because the process of CWD decay and associated ecological succession is known to take several decades in subalpine forests, we hypothesized that storm disturbance has long-lasting effects on fungal communities, their wood decay function, saproxylic bryophyte communities, and seedling establishment. To test this hypothesis, we surveyed fungal, bryophyte, and seedling communities at forest sites that had been disturbed by a large typhoon 55 years ago and compared them with those of surrounding undisturbed coniferous forest in central Japan. Contrary to our hypothesis, Illumina sequencing for the fungal ITS1 region in rDNA obtained from wood samples did not show that past disturbance had an obvious effect on current fungal communities. Also, the frequencies of occurrence of various wood decay types were not significantly different between disturbed and undisturbed plots. However, disturbance affected bryophyte communities, which had strong effects on the seedling densities of Picea jezoensis var. hondoensis , Tsuga diversifolia , and Betula spp. These results suggest that the previous typhoon disturbance in the focal area had long-lasting effects on biotic interactions and seedling regeneration on CWD, but these effects might not be attributable to the impacts of disturbance on CWD fungal communities and their wood decay function. [ABSTRACT FROM AUTHOR]

Highlights • Forests were investigated over 50 years after a severe windthrow. • Salvage logging noticeably reduced the amount of dead wood carbon stock. • Unsalvaged stands had a larger amount of dead wood than undisturbed stands. • Unsalvaged stands stored similar amounts of total woody carbon as undisturbed stands. • Thus, dead wood potentially offset the reduced live woody biomass. Abstract Windthrow disturbances often produce large amounts of dead woody materials in a forest. However, post-disturbance, salvage logging greatly reduces the amount of dead woody materials, and thus, carbon stocks. Because the dead woody materials can persist as coarse woody debris (CWD) for a very long time in cool climatic areas, such as boreal and subalpine forests, salvage logging might have long-term effects on the carbon stocks of disturbed forests. In this study, we examined the effects of windthrow by a super typhoon in 1959 and subsequent salvage logging on the carbon stock of subalpine forests more than a half-century after the disturbance in central Japan. We sampled disturbed and not salvaged (unsalvaged) stands versus disturbed and salvaged stands within 10 years of the disturbance (salvaged) in addition to undisturbed stands (undisturbed). The volume of CWD was higher in the unsalvaged stands versus the other two types of forests. Specifically, the volume of classes with intermediate decay was very high, contributing to greater carbon stocks of CWD in the unsalvaged stands. Although the carbon stock of living trees was higher in the undisturbed stands compared to the disturbed stands (unsalvaged and salvaged), the total carbon stock (live + dead) of the unsalvaged stands (104 Mg C ha−1) was almost equivalent to that of the undisturbed stands (99 Mg C ha−1) and was much higher than that of the salvaged stands (72 Mg C ha−1). This study demonstrates that CWD produced by a typhoon acts as a large carbon stock for more than a half-century, potentially offsetting the loss of live woody biomass in disturbed forests. [ABSTRACT FROM AUTHOR]

Climate changes are assumed to shift the ranges of tree species and forest biomes. Such range shifts result from changes in abundances of tree species or functional types. Owing to global warming, the abundance of a tree species or functional type is expected to increase near the colder edge of its range and decrease near the warmer edge. This study examined directional changes in abundance and demographic parameters of forest trees along a temperature gradient, as well as a successional gradient, in Japan. Changes in the relative abundance of each of four functional types (evergreen broad-leaved, deciduous broad-leaved, evergreen temperate conifer, and evergreen boreal conifer) and the demography of each species (recruitment rate, mortality, and population growth rate) were analyzed in 39 permanent forest plots across the Japanese archipelago. Directional changes in the relative abundance of functional types were detected along the temperature gradient. Relative abundance of evergreen broad-leaved trees increased near their colder range boundaries, especially in secondary forests, coinciding with the decrease in deciduous broadleaved trees. Similarly, relative abundance of deciduous broad-leaved trees increased near their colder range boundaries, coinciding with the decrease in boreal conifers. These functional-type-level changes were mainly due to higher recruitment rates and partly to the lower mortality of individual species at colder sites. This is the first report to show that tree species abundances in temperate forests are changing directionally along a temperature gradient, which might be due to current or past climate changes as well as recovery from past disturbances. [ABSTRACT FROM AUTHOR]

Intensive monitoring of multiple taxonomic groups is essential to understand ecosystem structure and function. In such studies, plant ecologists desire to monitor animal communities as efficiently as possible. We examined the efficiency of two trapping methods with different trap distances and total trapping areas for monitoring forest-floor rodent communities. We especially targeted two endemic, terrestrial, and semi-arboreal species dominating in forests throughout Japan. The long-distance (25 m) and the short-distance (10 m) methods assumed less than and more than one trap per female territory, respectively. Irrespective of species, capture efficiency tended to be higher in the long-distance than in the short-distance method. Recapture probabilities of two species were more similar in the short-distance than in the long-distance method in 2013. Observed densities for both species in the short-distance method were relatively similar to the estimated densities based on the long-distance method in 2011. In contrast, observed densities were lower than the estimated densities in the short-distance method in 2013. Observed densities of semi-arboreal species tended to be underestimated when only terrestrial traps were used. From these results, we propose that the short-distance method can efficiently estimate densities and community composition when researchers plan a small-effort study for a short time with a small area. In contrast, the long-distance method will allow researchers to estimate population densities robustly, when taking a large effort of a 3- to 4-day session with a large area. Our results also suggest that using both terrestrial and arboreal traps will improve the estimation. [ABSTRACT FROM AUTHOR]

Abstract: We examined whether the relative importance of facilitation and competition effects by an unpalatable perennial (Urtica thunbergiana) on a palatable annual (Persicaria longiseta) change with the spatial distance between them in a long-term deer-grazing habitat. Survivorship, growth, size, and fecundity of Persicaria were recorded at 1–2-month intervals during growing seasons in 2 successive years and were compared among individuals located in different positions relative to the canopy of Urtica: at the centre, internal edge, external edge, and far from the canopy. Survivorship of Persicaria was significantly higher at the centre of the Urtica canopy than outside the canopy early in the growing season in both years. No significant differences in Persicaria growth were observed among the four positions in most periods, except in one when growth was significantly higher at the centre, internal, and external edges of the canopy compared to outside the canopy. We found spatial shifts in the net effects of Urtica on Persicaria fecundity, from positive effects under the canopy centre to negative effects under the external edge of the canopy in the first year, and from negative effects under the centre to positive effects under the external edge in the second year. These results demonstrate that the relative importance of positive and negative effects of Urtica on Persicaria vary temporally within and among years and spatially around a single Urtica plant. Spatiotemporal variation in plant interactions may be attributable to annual and seasonal variation in vegetation productivity and grazing pressure. [Copyright &y& Elsevier]

• We incorporated regeneration on downed logs into LANDIS-II forest landscape model. • We revealed the long-term effects of post windthrow management on forest recovery. • Birch-dominated forests regenerated and persisted over 100 years at scarified sites. • Salvaging after a first windthrow delayed biomass recovery after a second one. • CWD-dependent species hardly recover after multiple windthrows in case of salvaging. Post-windthrow management delays forest biomass recovery by altering the situation of disturbance legacies and can change the species composition. Although the short-term effects of post-windthrow management have been well studied, we do not have enough knowledge about the long-term effects of post-windthrow management on species composition and biomass recovery. Those effects associated with an increase in the windthrow frequency are also unknown. Although forest landscape models can effectively evaluate these effects, conventional models do not represent the regeneration process on downed logs, which is essential for simulating forest succession. We focused on hemiboreal forests in northern Japan and aimed to (1) incorporate the regeneration process on downed logs into LANDIS-II, which is one of the most used forest landscape models; (2) evaluate the long-term effects of post-windthrow management on tree species composition and aboveground biomass recovery; and (3) evaluate the associated long-term effects of interactions between post-windthrow management and increased windthrow frequency. We incorporated the regeneration process on downed logs into LANDIS-II by regulating the probability of the establishment of species that depend on dead wood, such as spruce, according to the availability of well-decayed dead wood. The incorporation of this process resulted in simulations of trends in species composition and aboveground biomass recovery after post-windthrow management that were more accurate than those produced by the original model. In the modified LANDIS-II simulation, reductions in dead wood and advanced seedlings due to salvage logging had little effect on the tree species composition or aboveground biomass recovery; however, the complete destruction of advanced seedlings by scarification induced a delay in aboveground biomass recovery and a shift to birch-dominated forests that continued for 100 years. In addition, the reduction in dead wood due to salvage logging decreased the number of seedlings, especially of dead wood-dependent species, that established after windthrow. When the windthrow frequency doubled, this decrease in seedlings induced a delay in aboveground biomass recovery, and a substantial decrease in dead wood-dependent species biomass occurred after a subsequent windthrow event. However, after the second windthrow event and following scarification, the forest recovered in the same way as after the first windthrow because the destruction of advanced seedlings and understory plants, namely, dwarf bamboo (Sasa spp.), by scarification reset the site conditions. To conserve the species composition and aboveground biomass of hemiboreal forests under climate change, which is expected to increase windthrow frequency, salvage logging and scarification should be avoided. [ABSTRACT FROM AUTHOR]

Litter and soil organic matter decomposition represents one of the major drivers of carbon and nutrient cycling in a given ecosystem; however, it also contributes to a significant production of relevant greenhouse gasses. The Japanese archipelago spans several biomes (boreal‐temperate‐subtropical) and covers a large range of elevations and ecosystem types. Hence, the comprehension of this fundamental biogeochemical process in diverse ecosystems is crucial to maintain their ecosystem services. In this article, we have provided data on plant leaf decomposition from 33 research sites across Japan. At each site, standard litter material with different decomposition rates, rooibos tea and green tea were incubated for 90 days between 2012 and 2016 and the remaining mass was recorded. In total, 1904 bags were used. In addition, supplementary measurements of environmental variables essential for the interpretation of the collected data, such as soil and vegetation, were recorded. Plot‐level averages of the remaining mass rates of bag contents after incubation ranged 0.17–0.51 for green tea and 0.54–0.82 for rooibos tea. Continued monitoring will also provide important insights into the temporal dynamics of litter decomposition. [ABSTRACT FROM AUTHOR]

• Analysis on a 30-years observation data along a chronosequence of secondary forest. • Net biomass change has accelerated prior to 1980s, but has decelerated after 1980s. • Nitrogen and CO 2 rather than climatic factors might contribute to the acceleration. • Water stress, air pollutants and deer herbivory might contribute to the deceleration. Secondary forests are a huge carbon sink in terrestrial ecosystems, but it remains unclear whether growth of secondary forests has accelerated or decelerated due to global environmental changes, especially in East Asia. In this study, we analysed 30 years of data at 26 permanent plots along a secondary succession of temperate forest in central Japan to test whether the aboveground biomass (AGB) growth of secondary forest has accelerated or decelerated. The AGB–age relationship has clearly shifted upwards from the 1980s to the 2010s. The observed annual net AGB change (ΔAGB) was higher than that expected from the AGB–age relationship. These results indicate that ΔAGB has accelerated. However, the observed ΔAGB adjusted for the effects of stand age has gradually decreased from the 1980s to the 2010s. This indicates that ΔAGB of the secondary forest had accelerated prior to the 1980s, and decelerated after the 1980s. The decrease in ΔAGB after the 1980s was due to decreased biomass gain in the 1990s and increased mortality after the 1990s. Climatic factors are not considered the driver of the acceleration of ΔAGB because mean annual temperature and annual precipitation at the study site was relatively stable before 1980. However, mean annual temperature has increased since the 1980s and annual precipitation was low in the 1990s, which would result in increased drought stress and may have contributed to the decrease in biomass gain in the 1990s. Other abiotic and biotic stresses may also have contributed to the increased mortality after the 2000s. This study revealed a long-term transition from an acceleration phase to a deceleration phase of forest growth, indicating that forest growth changes relating anthropogenic environmental changes since mid-20th century are not necessarily unidirectional. [ABSTRACT FROM AUTHOR]

• We revealed long-term effects of salvaging after windthrows on total carbon stocks. • The total carbon stock almost recovered 64 years after the windthrow and salvaging. • Broadleaves and CWD generated after the windthrow have offset CWD lost by salvaging. • Well-decayed CWD and the organic layer carbon stock were low in salvaged forests. To mitigate the negative effects of climate change, it is necessary to conserve carbon stocks in forests. Typhoons fell many standing trees and generate a substantial amount of coarse woody debris (CWD). In boreal forests, CWD contributes to maintaining carbon stocks for a long time after a disturbance because the decomposition rate of CWD is relatively low. We know that salvage logging after a disturbance tremendously decreases the forest carbon stock over the short term after logging but know little about its long-term effects. We targeted a catastrophic windthrow caused by a super typhoon in 1954 in boreal forests in northern Japan and estimated the long-term effects of salvage logging after the windthrow on the above- and belowground carbon stocks by comparing old-growth forests with low damage from the super typhoon in 1954 or any subsequent typhoons (OG), forests damaged by the typhoon with remaining CWD (i.e., windthrow, WT), and forests damaged by the typhoon followed by salvage logging (WT + SL). The CWD carbon stock of decay class 5 (i.e., the most decayed CWD) in WT was significantly larger than that in OG and WT + SL, suggesting that the CWD in decay class 5 in WT had been generated by the typhoon 64 years ago, and the negative effect of salvage logging on the carbon stock still remains apparent in the CWD carbon stock of decay class 5. The carbon stock of the organic (O) layer in WT was larger than that in WT + SL, probably because of three factors: (1) the slower decomposition rate of fallen leaves and twigs of conifers than broadleaves, as conifer litter is abundant in WT; (2) greater carbon transition from the CWD to the O layer in WT; and (3) the occurrence of a lower decomposition rate in the O layer in WT. However, the total carbon stock in WT + SL has almost recovered to the level of that in WT within the last 64 years. The carbon stocks of broadleaves that grew rapidly after the disturbance and the newly accumulated dead trees generated throughout the stand developmental process might contribute to the recovery of carbon stock in WT + SL. These results indicate that salvage logging affects the allocation of carbon in the forest even after 64 years after a catastrophic windthrow, although there was no large difference in total carbon stock. [ABSTRACT FROM AUTHOR]